Device and method for treatment of atrioventricular regurgitation

ABSTRACT

A device and method for treatment of atrioventricular regurgitation comprises a suturing device. The suturing device is configured to be introducible, via blood vessels leading to the heart, to two leaflets of the atrioventricular valve between the atrium and a corresponding ventricle of the heart. The suturing device is configured for binding together the two leaflets along the free edges of the leaflets. A method of using the device includes inserting the suturing device into a catheter, introducing the catheter to the heart and positioning a distal end of the catheter close to two leaflets of an atrioventricular valve, capturing the free edges of the two leaflets with the suturing device in its open state, binding together the two leaflets by transition of the suturing device into its closed state, and retracting the catheter from the heart. As a result, the closing of the valve is improved.

This is a continuation of parent application Ser. No. 09/670,082 filedSep. 26, 2000, now U.S. Pat. No. 6,719,767.

BACKGROUND OF THE INVENTION

The invention relates to a device for treatment of atrioventricularregurgitation and a method for treatment of atrioventricularregurgitation using said device.

The heart has two atrioventricular valves, the mitral valve, which issituated between the left atrium and the left ventricle, and thetricuspid valve situated between the right atrium and the rightventricle. The tricuspid valve has three leaflets, two of which are muchbigger than the third. These two bigger leaflets could be considered tocorrespond to the two leaflets of the mitral valve. Therefore, only themitral valve will hereinafter be discussed although correspondingdiscussions could apply to the tricuspid valve.

Mitral regurgitation is the medical name of a problem that occurs in theheart. A person that suffers from mitral regurgitation has a mitralinsufficiency, i.e. the mitral valve between the left atrium and theleft ventricle cannot close entirely. Thus, when the ventricle iscontracted in order to pump out blood through the aorta, some bloodleaks back into the atrium instead. This will lead to a reducedfunctionality of the left ventricle and subsequently to heartinsufficiency, which is a mortal disease.

Mitral insufficiency can result from, for example, ischemic disease,degenerative disease of the mitral apparatus, rheumatic fever,endocarditis, congenital heart disease and cardiomyopathy. The fourmajor structural components of the mitral valve are the annulus, the twoleaflets, the chordae and the papillary muscles. Any one or all of thesein different combinations may be injured and create insufficiency.

At present mitral regurgitation is treated by open-heart surgery. Thisis a major operation and requires the use of total cardiopulmonaryby-pass, aortic cross clamping and cardioplegic arrest. To certaingroups of patients this is particularly hazardous and there is anapparent risk of not surviving the operation.

The treatment consists of either mitral valve replacement or repair.Replacement can be performed with either mechanical or biologicalvalves.

The mechanical valve carries the risk of thromboembolism and requiresanticoagulation, with all its potential hazards, whereas biologicalprostheses suffer from limited durability. Another hazard in connectionwith replacement is the risk of endocarditis. These risks and othervalve related complications are greatly diminished with valve repair.

The four basic techniques of repair include the use of an annuloplastyring, quadrangular segmental resection of diseased posterior leaflet,shortening of elongated chordae, and transposition of posterior leafletchordae to the anterior leaflet. The techniques of mitral valve repairrely on decreasing valve area to increase leaflet apposition, but failto address subvalvular dysfunction. Mitral insufficiency caused byprolapse of the anterior leaflet, posterior leaflet with calcifiedannulus, or prolapse of both leaflets constitutes a more demandingchallenge to repair.

In 1995 Alfieri et al introduced modifications in the operativetechnique that allow a more expeditious and reproducible procedure thanthe traditional of greater complexity. This is achieved by simplyanchoring the prolapsing free edge of the leaflet to the facing edge ofthe other leaflet (edge-to-edge technique), thus creating a doubleorifice of the mitral valve. The hemodynamic behavior of a doubleorifice mitral valve does not differ from that of a physiological valveof the same total area. Pressure drops and flow velocity across thevalve are not influenced by the configuration of the valve.

Some efficient methods of treating mitral insufficiency exist as shownabove, but all of them require open-heart surgery. Since many patientswith mitral regurgitation are elderly or have a poor left ventricularfunction, they would benefit from a less invasive procedure that doesnot involve the use of cardiopulmonary by-pass as required byconventional techniques.

SUMMARY OF THE INVENTION

The object of the invention is to provide a device and a method fortreatment of atrioventricular regurgitation that will be applicable to abeating heart.

Thus, a device for treatment of atrioventricular regurgitation comprisesa suturing means having such dimensions as to be introducible, via bloodvessels leading to the heart, to two leaflets of an atrioventricularvalve between an atrium and a corresponding ventricle of the heart andbeing designed for binding together the two leaflets in a position alongthe free edges of the leaflets, whereby the closing of theatrioventricular valve is improved.

Preferably, the atrioventricular valve is the mitral valve between theleft atrium and the left ventricle of the heart.

Diseases to the atrioventricular valves are much more common in themitral valve than in the tricuspid valve. Therefore the focus of theinvention is on the treatment of the mitral valve although treatment ofthe tricuspid valve could work equally well using the device.

The suturing means is preferably transitional between two states, beingopen in a first state and substantially closed in a second state.

This makes the suturing means capable of reaching the free edges of themitral leaflets in the first state and of bringing them closer to eachother when transitioned into the second state.

In a preferred embodiment, the suturing means comprises a clip.

Preferably, the clip has two arms pivotally connected to each other at afirst end thereof, the arms forming a V in the first state of the clipand being substantially parallel in the second state of the clip.

Consequently, the arms of the clip can capture both mitral leaflets inthe first state and bring them closer together in the second state.

Desirably, the arms of the clip have second, free ends bent towards eachother so that these ends of the arms in the second state of the clip arebrought proximal to each other.

This means that the mitral leaflets can be brought in close proximity tocreate a suture as the ends of the arms capturing the mitral leaflets inthe second state of the clip are brought proximal to each other.

Further, each second end of the arms is preferably sharp.

As a result, the clip can easily capture the mitral leaflets and arecapable of gripping the leaflets between its arms.

Suitably, the clip has two pairs of arms connected to each other by twocrossbars near the connected first ends of the arms.

This means that the clip can get a good and lasting grip on the mitralleaflets.

Preferably, the device comprises a catheter for introduction of the clipvia the blood vessels into the heart, said catheter having an outermostsheet covering the clip and being retractable therefrom.

This allows the clip to easily be introduced into the heart and there beuncovered for application to the mitral valve.

In one embodiment the catheter has a rod for holding the clipsubstantially in the open state within the outermost sheet and anapplicator for pushing the clip off the rod for transition thereof intothe closed state when the outermost sheet is retracted from the clip.

This is desirable for the application of the suturing means, as thetransition between the two states of the suturing means can becontrolled for capturing and suturing of the mitral leaflets.

In another embodiment the catheter has a rod for holding the clipsubstantially in the open state within the outermost sheet, said rodalso having a puncturing means at a distal tip thereof.

This means that the catheter can be introduced via a vein since thepuncturing means can be used to puncture the interatrial septum so as toenable the device to be brought into the left atrium from the rightatrium.

Preferably, the suturing means consists of a memory material such asNitinol.

As a result, the suturing means can easily be made to transform from itsfirst state to its second and thereafter maintain its second state.

According to the present invention, the method for treatment ofatrioventricular regurgitation comprises the steps of providing asuturing means having an open state and a closed state; inserting thesuturing means into the distal end of a catheter; introducing thecatheter via blood vessels leading to the heart, so as to position thedistal end of the catheter close to the free edges of two leaflets of anatrioventricular valve between an atrium and a corresponding ventricleof the heart; capturing the free edges of the two leaflets with thesuturing means in its open state; binding together the two leaflets bytransition of the suturing means into its closed state; and retractingthe catheter from the heart while leaving the suturing means fixed onthe two leaflets.

Preferably, the atrioventricular valve is the mitral valve between theleft atrium and the left ventricle.

Preferably, the suturing means is covered with a protective sheet of thecatheter when introduced into the distal end thereof and uncovered byretraction of the protective sheet when positioned close to the freeedges of the two leaflets of the atrioventricular valve.

Consequently, the suturing means can be introduced into the heart in aconvenient way and be exposed in the ventricle.

In a mitral valve embodiment of the invention the catheter is introducedinto the brachial or femoral artery and is passed retrograde to theblood flow through the aorta to the left ventricle.

In another mitral valve embodiment the catheter is introduced into avein and passed up to the heart via the vein. The catheter could beintroduced through any suitable vein, such as the femoral, jugular orsubclavian veins. In this embodiment, the catheter preferably has apuncturing means on a distal tip thereof, such that the interatrialseptum may be punctured by said puncturing means and the catheter beintroduced through the septum to the left atrium and then passed to theleft ventricle.

This means that the catheter may be introduced through the femoral veinsince a passage from the right side of the heart to the left side isachievable.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by means of the followingdescription of preferred embodiments referring to the accompanyingdrawings, in which

FIG. 1 is a partially sectional view of a heart having a suturing meansapplied on the mitral valve according to the present invention;

FIG. 2 is a perspective view of a suturing means according to thepresent invention;

FIG. 3 is a sectional view of a catheter carrying a suturing meansaccording to one embodiment of the invention;

FIG. 4 is a perspective view of the catheter in FIG. 3 carrying asuturing means that has been unsheathed;

FIG. 5 shows schematically how a device according to the invention canbe inserted through an artery into the left ventricle of the heart;

FIG. 6 is a sectional view of a catheter carrying a suturing meansaccording to another embodiment of the present invention;

FIG. 7 is a perspective view of the catheter in FIG. 6 carrying asuturing means that has been unsheathed according to another embodimentof the invention; and

FIG. 8 shows schematically how a device according to the invention canbe inserted through a vein into the left ventricle of the heart.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The device will now be described with reference to its use on a mitralvalve. However, it is obvious that the device could also be used on thetwo biggest leaflets of the tricuspid valve.

FIG. 1 shows a heart 1. The left side of the heart 1 is shown insection. A clip constituting a suturing means 2 is applied to the freeedges of the mitral valve 3 keeping the mitral leaflets 4, 5 together ina connection point so as to create a double orifice, one orifice on eachside of the connection point, thus allowing the leaflets 4, 5 to closecompletely.

In the following there will be described a device and a method forcreating a double orifice in the mitral valve 3 of a beating heart 1.

Referring now to FIG. 2, an enlargement of the suturing means 2 isshowed. The suturing means 2 being a clip consists of two pairs 6, 7 ofarms 8–9 and 10–11. The arms 8–9 and 10–11 in the pairs are connected inone end 14, 15 and thus are formed in one piece. In their other end thearms 8–9 and 10–11 are bent towards each other in a bent portion 16. Thebent portions 16 are terminated with a sharp tip 17 so as to be able toengage and grab the mitral leaflets 4, 5.

The clip 2 has two parallel crossbars 12, 13 that each connect one arm8, 9 in one pair 6 to one arm 10, 11 in the other pair 7. The crossbars12, 13 are equally long and are connected to the arms 8–9 and 10–11 atequal distance from the connections 14, 15. The pairs 6, 7 of arms arethus kept parallel by the crossbars 12, 13. The crossbars 12, 13 areattached to the arms 8–9 and 10–11 near the connection ends 14, 15.

The clip 2 is made of a memory metal, such as Nitinol, and in FIG. 2 itis shown in a second state where the arms 8–9 and 10–11 in the pairs areparallel and the bent portions 16 in their ends are brought in closeproximity to each other. The memory material of the clip 2 biases theclip 2 towards its second, closed state. In a first state, the arms 8–9and 10–11 in the pairs are opened, forming a V, as the angle in theirconnections 14, 15 is increased. The clip 2 is capable of grasping themitral leaflets 4, 5 at their free edges and bind the edges together bycapturing the leaflets 4, 5 in the first state of the clip 2 and keepingthem together in the second state of the clip 2, where the arms areclosed and parallel.

The clip 2 is inserted into a beating heart 1 by using a catheter.Referring to FIGS. 3 and 4, a first embodiment of a catheter 18 will bedescribed. In its innermost part the catheter 18 has a supportive rod 19that is slidable in a hollow applicator 20. In its outermost part thecatheter 18 has a protective sheet 21 that also is slidable upon theapplicator 20.

The clip 2 is attached in a distal end of the catheter to the applicator20. The attachment is made in the connections 14, 15 of the arms 8–9 and10–11 in the pairs. The supportive rod 19 can be extended out of theapplicator 20 and be held between the two crossbars 12, 13 of the clip2. The supportive rod 19 does in this condition hold the arms 8–9 and10–11 in the pairs of the clip 2 apart, keeping the clip 2 in its first,open state. The protective sheet 21 can be pushed over the clip 2 tomake the catheter 18 easier to introduce into the heart 1 and keep thearms 8–9 and 10–11 in the pairs parallel from the crossbars 12, 13towards the bent portions 16 as shown in FIG. 3, the clip 2 still beingheld substantially in the open state. In this way the clip 2 does notget stuck as it is passed into the heart 1.

In FIG. 4 the protective sheet 21 is drawn back along the applicator 20,thus uncovering the clip 2 and allowing the clip 2 to take the form ofits first state. The clip 2 can then be transformed into its secondstate by retracting the supportive rod 19 that keeps the crossbars 12,13 of the clip 2 apart.

A second alternative embodiment of the catheter 18′ is shown in FIGS. 6and 7. The catheter 18′ comprises a supportive rod 19′ that in thedistal end of the catheter can be entered and held between the twocrossbars 12, 13 of the clip 2 and extend past the connection ends 14,15 of the arms 8–9 and 10–11 in the pairs. The supportive rod 19′ doesin this condition hold the arms 8–9 and 10–11 in the pairs of the clip 2apart, thus keeping the clip 2 in its first state.

In its distal end the supportive rod 19′ has a needle 22 that can beused to puncture the interatrial septum. The catheter 18′ has anoutermost protective sheet 21′ that is slidable upon the supportive rod19′. When the catheter 18′ is inserted into the heart 1, the protectivesheet 21′ covers the clip 2 keeping the arms 8–9 and 10–11 in the pairsparallel from the crossbars 12, 13 towards the bent portions 16 as shownin FIG. 6 and also covers the needle 22 of the supportive rod 19′.However, the clip 2 is still held substantially in the open state withits free ends 16 apart. As the protective sheet 21′ is drawn back, itfirst uncovers the needle 22 allowing it to puncture the interatrialseptum and then uncovers the clip 2 allowing it to take the form of itsfirst state. The supportive rod 19′ can then be retracted making theclip 2 transform into its second state.

The catheter 18, 18′ could also have an ultrasound probe to provide aneasy way for visualizing the device inside the heart 1. The supportiverod 19, 19′ could be designed to also provide the ultrasound probe.Ultrasound could also be used in other ways for visualization, e.g. byinserting an ultrasound probe inside the oesophagus.

Two alternative methods for inserting the device for treating mitralregurgitation will be described in the following. The insertion is doneinto a beating heart and can be performed in local anesthesia.

Both methods include an introduction of a catheter into the heart. Theseintroductions described below are standard techniques currently used fordiagnostic left heart catheterization.

The first method uses the catheter 18 shown in FIGS. 3 and 4. Referringto FIG. 5, the catheter 18 is inserted into the body through thebrachial or the femoral artery. The catheter 18 is then passedretrograde along the artery into the left ventricle of the heart 1. Theprotective sheet 21 is then retracted as shown in FIG. 4, thusuncovering the clip 2. The clip 2 is now in its first, open state and isused to capture the mitral leaflets 4, 5, preferably in the middle oftheir free edges. The sharp ends 17 of the bent portions 16 of the arms8–11 give a steady grip on the mitral leaflets 4, 5. The supportive rod19 is then retracted, thus allowing the clip 2 to transform into itssecond state. The clip 2 thereby closes and keeps the captured parts ofthe two mitral leaflets 4, 5 together. The clip 2 is now in place tograsp and approximate the free edges of the mitral leaflets 4, 5 by theedge-to-edge technique. A double orifice, one on each side of thesuture, is thus formed. This double orifice can be closed completely bythe mitral valve. Finally, the catheter 18 is retracted from the heart1, leaving the clip 2 forming the double orifice.

The second method uses the catheter 18′ shown in FIGS. 6 and 7. Thecatheter 18′ is inserted into the body through the femoral vein. Thecatheter 18′ could be inserted through any other suitable vein, such asthe jugular or the subclavian vein. Referring to FIG. 8, the catheter18′ is passed along the femoral vein into the vena cava and further intothe right atrium. The needle 22 in the distal end of the supportive rod19′ is unsheathed by a retraction of the protective sheet 21′ of thecatheter 18′. The needle 22 is then used to puncture the interatrialseptum to give the catheter 18′ a passage into the left atrium and thenthrough the mitral valve into the left ventricle. When the catheter hasbeen passed into the left ventricle, the protective sheet 21′ isretracted further, whereupon the clip 2 unfolds. The clip 2 is now inits first, open state and the mitral leaflets 4, 5 can be captured inthe same manner as described for the first method. When the supportiverod 19′ is retracted, the clip 2 transforms into its second state, thusclosing and keeping the mitral leaflets 4, 5 together. The clip 2 is nowin place to grasp and approximate the free edges of the mitral leaflets4, 5 by the edge-to-edge technique. As for the first method a doubleorifice that the mitral valve can close completely is created. Finallythe catheter 18′ is retracted completely from the body leaving the clip2 forming the double orifice.

When treating tricuspid regurgitation the catheter 18′ is used withoutthe needle 22 on the distal end of the supportive rod 19′. The catheter18′ is inserted into the body through a vein, such as the femoral,jugular or subclavian veins. The catheter 18′ is passed along the veininto the right atrium of the heart 1. The catheter 18′ is then insertedthrough the tricuspid valve into the right ventricle. Here theprotective sheet 21′ is retracted to uncover the clip 2 and the captureof the two biggest leaflets of the tricuspid valve could be performed inthe same manner as described for the mitral valve described above.Finally, the catheter 18′ is retracted leaving the device fixed on twoleaflets of the tricuspid valve.

Although particular embodiments of the present invention have beendescribed, the application is not limited to these embodiments butincludes modifications that are obvious to the skilled man and arecomprised in the scope of the invention as defined in the appendedclaims. For example, it is obvious that different embodiments of clipscan be designed. Modifications of the suturing means are possible innumerous ways without extending beyond the spirit of the invention.

1. A method of stabilizing a first heart valve leaflet in a heart,comprising: providing a delivery catheter; providing a clip formed froma temperature-activated memory material; securing the clip in a deliverystate to the delivery catheter; advancing the clip to a desired positionadjacent the first heart valve leaflet; transforming the clip from thedelivery state to an open state, wherein the clip is in an open positionwith a clip opening configured to receive an edge of the first heartvalve leaflet; positioning an edge of the first heart valve leafletwithin the clip opening; and transforming the clip from the open stateto a closed state, whereby the edge of the first heart valve leaflet issecured within the clip.
 2. The method of claim 1, wherein the memorymetal of the clip biases the clip toward the closed state.
 3. The methodof claim 2, wherein securing the clip in the delivery state to thedelivery catheter comprises mechanically biasing the clip toward theopen state and mechanically holding the clip in the delivery state. 4.The method of claim 3, wherein transforming the clip to the open statecomprises releasing the mechanical holding of the clip in the deliverystate.
 5. The method of claim 1, further comprising: prior totransforming the clip to the closed state, positioning an edge of asecond heart valve leaflet within the clip opening, whereby when theclip is transformed to the closed state the edge of the second heartvalve leaflet is secured within the clip.
 6. An apparatus for securing afirst heart valve leaflet, the apparatus comprising: a clip comprising afirst end and a second end, the clip having an open state, a deliverystate, and a closed state, the clip comprising a memory metal and beingbiased toward the closed state; and a delivery catheter, the deliverycatheter comprising a first member configured to mechanically bias theclip toward the open state, and a second member configured tomechanically bias the clip toward the delivery state.
 7. The apparatusof claim 6, wherein the delivery catheter has a distal end and furthercomprises a needle at the distal end, the needle configured to puncturean interatrial septum of a patient's heart.
 8. The apparatus of claim 6,wherein the delivery catheter first member comprises a supportive rodconfigured to engage the first end of the clip.
 9. The apparatus ofclaim 8, wherein the supportive rod comprises a distal end having aneedle thereon, the needle configured to puncture an interatrial septumof a patient's heart.
 10. The apparatus of claim 9, wherein the deliverycatheter comprises a generally tubular outer member, and the supportiverod is slideable within the generally tubular outer member.
 11. Theapparatus of claim 6, wherein the delivery catheter second membercomprises a generally tubular member configured to slideably receive theclip, thereby engaging the second end of the clip and mechanicallybiasing the clip toward the delivery state.
 12. A method of stabilizinga first heart valve leaflet in a heart, comprising: providing a deliverycatheter; providing a clip formed from a memory material; securing theclip in a delivery state to the delivery catheter; advancing the clip toa desired position adjacent the first heart valve leaflet, whereinadvancing the clip comprises advancing the clip into the right atrium ofthe heart, puncturing the interatrial septum of the heart, and advancingthe clip through the interatrial septum and into the left atrium of theheart; transforming the clip from the delivery state to an open state,wherein the clip is in an open position with a clip opening configuredto receive an edge of the first heart valve leaflet; positioning an edgeof the first heart valve leaflet within the clip opening; andtransforming the clip from the open state to a closed state, whereby theedge of the first heart valve leaflet is secured within the clip. 13.The method of claim 12, wherein the memory metal of the clip biases theclip toward the closed state.
 14. The method of claim 13, whereinsecuring the clip in the delivery state to the delivery cathetercomprises mechanically biasing the clip toward the open state andmechanically holding the clip in the delivery state.
 15. The method ofclaim 14, wherein transforming the clip to the open state comprisesreleasing the mechanical holding of the clip in the delivery state. 16.The method of claim 12, further comprising: prior to transforming theclip to the closed state, positioning an edge of a second heart valveleaflet within the clip opening, whereby when the clip is transformed tothe closed state the edge of the second heart valve leaflet is securedwithin the clip.